The invention pertains to semiconductor processing methods and semiconductor constructions. In particular aspects, the invention pertains to dual-damascene processing methods, and to structures formed during dual-damascene semiconductor processing methods.
Semiconductor processing frequently involves formation of an electrical contact to a conductive structure. For instance, semiconductor devices frequently comprise a substrate having numerous electrical components supported therein and thereover, and above the electrical components are provided one or more metal layers. The metal layers can electrically connect the components to one another, and can be further utilized to electrically connect circuitry associated with a semiconductor device to other circuitry external of the device. The metal layers can be referred to as a metal I layer, metal II layer, metal III layer, metal IV layer, etc; with the numeric designation indicating the approximate level of the metal layer relative to the semiconductor circuit components. For instance, the first metal layer formed over the components will typically be referred to as a metal I layer, and the various other layers formed over the metal I layer will be numbered in ascending, sequential order. Electrical contacts are ultimately to be formed to electrically connect the various metal layers to one another, as well as to electrically connect the metal layers with the circuit components of the semiconductor device.
One method of forming electrical interconnects between elevationally separated conductive components is a damascene process. An exemplary damascene process is described with reference to FIGS. 1-5.
Referring initially to FIG. 1, a fragment of a semiconductor construction 10 is illustrated. The fragment comprises a semiconductor substrate 12 having an insulative mass 14 thereover. Substrate 12 can comprise, for example, monocrystalline silicon. To aid in interpretation of the claims that follow, the terms xe2x80x9csemiconductive substratexe2x80x9d and xe2x80x9csemiconductor substratexe2x80x9d are defined to mean any construction comprising semiconductive material, including, but not limited to, bulk semiconductive materials such as a semiconductive wafer (either alone or in assemblies comprising other materials thereon), and semiconductive material layers (either alone or in assemblies comprising other materials). The term xe2x80x9csubstratexe2x80x9d refers to any supporting structure, including, but not limited to, the semiconductive substrates described above. In exemplary constructions, substrate 12 can comprise various conductive, semiconductive, and insulative semiconductor device components (not shown), in addition to monocrystalline silicon.
Insulative mass 14 can comprise, for example, borophophosilicate glass (BPSG).
A conductive structure 16 is illustrated to be supported within insulative mass 14. Conductive structure 16 can comprise a semiconductor device component, or alternatively can comprise a metal layer, such as, for example, a metal I layer.
A patterned masking material 18 is formed over insulative mass 14. Masking material 18 can comprise, for example, photoresist, and can be patterned into the shown shape utilizing photolithographic processing methods. Patterned masking material 18 has an opening 20 extending therethrough, which exposes a portion of insulative mass 14.
Referring to FIG. 2, the exposed portion of insulative mass 14 is removed to extend opening 20 to conductive structure 16.
Referring to FIG. 3, masking layer 18 (FIG. 2) is removed, and a sacrificial, protective material 22 is formed across an upper surface of mass 14 and within opening 20. Material 22 can comprise, for example, anti-reflective coating (ARC) materials, such as, for example, bottom anti-reflective coating (BARC) materials. An exemplary BARC is DUV 42P, available from Brewer Science Corporation. Material 22 can be considered to comprise a first portion on an upper surface of mass 14, and a second portion within opening 20.
After formation of protective material 22, a patterned masking layer 24 is formed over the first portion of material 22. Masking layer 24 can comprise, for example, photoresist, and can be patterned by photolithographic processing. Material 24 defines a second opening 26 which overlaps with the first opening 20.
Referring to FIG. 4, an etch is conducted to extend second opening 26 through the first portion of protective material 22 and into mass 14. The second portion of material 22 within opening 20 protects conductive structure 16 from being exposed to the etching conditions. A difficulty can occur during the etch in attempting to remove the first portion of protective material 22 that is over mass 14. Specifically, it is difficult to find an etch which is selective for ARC or BARC relative to photoresist masking layer 24, and accordingly some of the masking layer 24 is removed during the etch. Such removal of masking layer 24 is illustrated by dashed lines 28 which show the starting position of material 24, and illustrate that material 24 has retreated from opening 26 during the etch of material 22. Such causes a widening of opening 26, and hence an increase in the critical dimension of opening 26. The widening of opening 26 also decreases a space between opening 26 and an adjacent opening or feature (not shown). A continuing goal in semiconductor processing is to reduce a footprint of various devices relative to a semiconductor substrate in order to conserve valuable semiconductor real estate. The increase in the critical dimension of opening 26 is therefore not desired.
Referring to FIG. 5, materials 22 and 24 (FIG. 4) are removed from over mass 14 and conductive structure 16. A difficulty can occur in removing BARC and ARC materials, in that polymers can be formed which deposit over conductive material 16, and which are difficult to selectively remove relative to conductive material of structure 16. For instance, structure 16 will frequently comprise, consist essentially of, or consist of copper; and it can be difficult to remove polymatic materials relative to copper without having at least some etching into the copper. The etching into the copper can detrimentally effect performance of circuitry utilizing conductive structure 16.
After removal of materials 22, and 24, the openings 20 and 26 can be filled with a suitable conductive material (not shown) to form an interconnect to conductive structure 16. In particular embodiments, opening 20 will be a via which extends to conductive structure 16, and opening 26 will be a slot. Accordingly, conductive material formed within openings 26 and 20 comprises a conductive line within slot 26 which is electrically connected to conductive structure 26 through a conductive interconnect defined by the conductive material formed within via 20.
In one aspect, the invention encompasses a dual-damascene semiconductor processing method. A semiconductor substrate is provided. The substrate includes a conductive structure and an insulative layer over the conductive structure. A via is etched through the insulative layer and into the conductive structure, and a resist is formed within the via. A material is formed over the resist and substrate. A portion of the material in contact with the resist is hardened, and another portion of the material that does not contact the resist is not hardened. The portion of the material which is not hardened is removed, and a slot is etched into the insulative layer. The resist and hardened portion of the material protect the conductive structure during the etching of the slot.
In another aspect, the invention encompasses a semiconductor processing method in which a first opening is formed to extend into a substrate. The first opening has a periphery at least partially defined by the substrate. A mass is formed within the first opening to only partially fill the first opening. A material is formed over the mass and within the partially-filled opening. At least one substance is released from the mass, and such substance forms chemical cross-links within the material. After the chemical cross-links are formed, at least some of the periphery of the first opening is removed to form a second opening. After the second opening is formed, the mass and cross-linked material are removed from the first opening.
In yet another aspect, the invention encompasses a semiconductor construction. The construction includes a semiconductor substrate which comprises a conductive mass and an insulative mass over the conductive mass. An opening extends through the insulative mass and to the conductive mass. A first organic material is formed within the opening and covers the conductive mass. The first organic material only partially fills the opening. A second organic material is within the partially-filled opening and over the first organic material. The second organic material is different than the first organic material.